Headlight.



F. D. SHENK 6: R. H. HOLMAN HEADLIGHT.

APPLICATION HLED DEC. 16, I915. 1,224, 12 1 Patented May 1,1917.-

3 SHEETS-SHEET 2.

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F. 0. SHENK & R. HJHOLMM.

HEADLIGHT.

ICATIQN FILED DEC-15,1915.

1,224,421, v ""3 Patented May 1, 1917. 3 ssssssssssss a.

Hall.

In at 22 tons RaZphiZ/fol 112ml I 710110330. 6726 n It AZio'rnc1/ zo oe. 1 r :iully1' (liscussed,hereinafter and to overcome wh1chourfinvention is directed.

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s momos 9! aut obile efliand the-like,hnd' Particularly tel illumination of that field or area withmfiwhichwthe attention ofa' driver is 1'5-rkaquifedandintowhich'the driver ofsjn apgproiichl ficmrior s. flp i' i g tr- ""iflThe requifeliients .-.ee, to elimination of aise crtaini.difliculties inaddition adyfl ecognized which will be,

pedestrian may be com- Our present invention contemplates aidevice 'whichsflwill in aisi'mple and nexpensiv to glare with t sac cin'g any material art oiE-the illuminetiveeificiency of the headlight'f'so that not onl-vlthieroad itself, but

the s we at each side zi form fulfil.- all' these imgosed conditions tile-.

so will} I efg iu-lly illuininatdin order;- to avoid accidentsicaused'b. "the sudden' :o ff

pedestrians-front e'curbor the flrotru of-=obetructionsiromthe s'ide. 5

' Harare-"16m into any "description of; stmeture it may be remerkedthattheprob- -.jle1,u of overeomin ;g'1are inyolves an ex; istingjfcohdition; at is, to say, the. die.

culty "must b'ecorrected for headlight constructionsalready, existence as w ell he 49' for those ofv the future/'- First, 'theusueiz'heedlight reflector or lens; while intended to Igive'fr'ays trulymeralleh Thee sufiicient e'r'fection' to actua l F accomplish this, resu t. Furthermore; iegusual sou rceoi lightwhich is now an incandescent j bulb isnot only of-courseyi greeter than the theoreticuli foes.

' lfnmkesf'of ileni syso 'amen' being inore Z re lohgrtudina'iqAll an; ebsolutelyitrue focus. conical. shieafwvithmore y's 'accord" g. to circumor en focus. The (Predifiuted on good focus i erstood that the disclosure we t-menus 5t enditfwill been point 'veries'in dilie'ren't fthe cone of rays '80 t mnuenr.

1a, 1915. Serial Ho. 67-5105.

herein isbased on the besti originel-focus of the lamps possible under the individual conditions. P The light from a' usual'so'urce placed in the focus of a pa; ebolic reflector or simple "mirror of a. headlj ght is sent forward in a slightly diver ing ,cone of'light with its axis 'dlr'ectly eyel' with the road surface.

Where thissurfateintersects the cone of light lies the'illulr inated 'area available for 05 seeing the roadwa' y. This obviouslytakes the form of the or mic section, commonly a long parabola. I r

Inorder toeyoid dazzling the observer various schemes lave: been devised. The 70 'jsimplemanner is 10 deflect the li ht below theeye of the average observer. y doing this at any point i1 front of the headli ht,'

the coneof rays mustbe de this. 11 per portior will-be elow' the line'zb jof-sig 'tmorder that its upper limit she-11' be motion-11y horizontal.

he efi'ect of this'i's' to-cause the lower margin of; the cone to intersectthe roadsur- "light than before, -and.to-.produce on the roadway along, illuminated surface mela- Letters rum. x l'atented May 1, 1917.

ressed so t at face st in. point considerably nearer the headlSO tivelyparabolie of which the nearer'portion of the interce tifextae'ediri'gl bright in I acoordancewit tie laiv of 11g t intensity 815 with the-variation ofiihe distance, and the remote portion in ly darker. Between the bright point '0 theiilluminated .surf eceendlthe-he edli'ght willviie a-badly lighted-section of greater-or less area but"" one. ofthe greatest. mportance-both inde- .pe dently and relatively. In-other words, I nth contrast-between'an excessive illumina- "tio'u some, distance ahead of'the car and. an. illuminated or dark space immediately in flfrontof'jthe car is an element, of danger.

,'1he purpose of our'im rovementfisi tof elfect theredistribution 0 light emerging fronr-the headlighm so that its projection on the roadway shall befi s nearly uniform in 10 this end, vve'provuie means to avoid, lare by depressing the cone of rays throug the f" necessary 'angle, in practice about half its" ungular diameter, an id insuch condition that 10 such added means redistril'lute.the light n projectionsh'l its reach the required distribution, ..,';""Preferab1y, we en ployfor dep rays 1 set of parollzl depressing; I

distribution as conditions will permit. To;

' through a specific angle.

ranged somewhat as 'inthe' familiar'prismatic lassused for windows but proportioned deflect the cone of rays "downward These do ressor prisms tip down the entire cone of lig tb'elow the required point. In addition to this we employ independently or in cmlsolidation distributin prisms to correct the misplacement of e illuminaside of the screen opposite the depressing prisms, or their angles may-merely be added to the depressing prisms um'nservessd that some or all of these will have their angles augmented or decreasedbythe amount necessary' to give a proper redistribution. Likewise, the prisms added to secure lateral dis-- tribution may be independently formed on n the external or internal face'of the refractvertical redistribution. by augmenting the angles of the .depressing prisms to such an extent as should be neoessar ing screen'in'such place and of sucharea as to produce the desired result. I

We prefer to meet the simple ordinary requirements of redistribution to obtain a and obtain horizontal redistribution by arming pris'- mati'cphas'es with vertical axes on the front of the reversingjscreeir or .even by providing a II'Qnt with a general curvature to a vertical axis.

.- prismatic elements the whole construction has two func tionsf'first, the depression of the rays, and

second, "the redistribution; which functions may be made by 'two entirely distinct sets of or by combination {as may desirable. To carry outithese require independent or combined as co'nveniencedie tates ,with the other prisgziatic elements. Second; prisms designed to ke light from that point whiehhas' become relatively overillumi'nated on account of the depression of the parabolic light area of the lightcon and its change of intercept" and to draw 'it backward toward the headlight to eliminate the qfiherwise dark space betwein the contact of the lower edgev ofjthe de" tossed Third, Pr me-teasers with s has; .trom 'the hm "portioiqte'lighd Me of producing the vention.

in'F1g.' 5 an" v nation or-interd'ept 'withthe roadway,

cone of light with the road level an the headlight.

.area existing as above and it nearer the horizonta so asto illuminate more brightly the distant portions-of the roadway. Fourth, the risms with refract-, ing edges at right or ob ique anglesto those herein efore mentioned to deflect'light from the brighter part of thebeam laterally to.

produce approximately uniformireflectioni of the beam sidewise toward the margins of 'the roadway.

' We have thus the depressor prisms andin .addition three types of' redistributing prisms, the angles of which are-designed v v produce the three specified results. It should bepnderstood thatan of these prismatic elements may be repla .byaquiV; I alen't lenticular elements, as ;.Q01 QiI nce-'of design may dictate, without departing from the spirit of our invention;

In the accompanying drawings we. have 73 illustrated both the conditions which must be coped with and the, means by which we overcome the dificulties incident to the requirements of gnawing the general resultant illumination.

e drawin relating to the. former are necessarily are hot illustrative of the liiinciples of-our invention and practical-emdiments. 'oapa-.

Fig.'2 is a plan view of-the same,

its intercept with the road level.'

the conical beam depressed.

F-g. 4 is a plan view of the beam shown in Fig. 3 showing the proximity of its intercept to thef-iieadlight.

glare elimination, while imr v iagrammatic, and 'theviewsi; V .treatin the latter show embodiments which practicalresults indi I divergent beam from the usual headlight, I

iu a is a Vie similar to Fig. 1 was Fig. 5 is a diagrammatic s1deriewof-the A beam from a Fig. e is strating' its .dligh dyingi oiir; in?

Fig. 7 is a rear elevation of a lightscreen v or plate in accordance with onr"inv'ent ion. a s W Pr vide first, depressing PIlSmS, which may be headlights; r

.Fig. :10 is;-

Fig. 8 is a. centrplseotion'al vi'ew'thereo'f; Fig. I 9 -is, .a dimmuse view indicating the lateralydi vergenoe of lights p from a pair of screensorplates on adiwent embodying ourinventionfwith the-severe classes of prisms and their efiects'c'learly 'diflerent ated, vi. e., the-depression t-"n' il;

the, augmented prisms to deflect. ii

the car,,t he;;dec re'ased risms to iminitsh. the depression (which ecrea'se may annul" or reversethe depression prisms) and finally belm 'al sv i s. P i m widen t '-1 ".-'1s0" Fig. 11 is a section on theline w-m of I modified in difl Brentpartsthereofso at Fig. 10.

a d the portion I'f'tf over-illumination H ferri first to the generalconditions t shall be dispelsed part of it being drawn of: headlig t illumination with particular backward or downwardv to form lateralwf" reference to FigsLl to 6 inclusiveit will be areas I of reasonable 'bri htne'ss to show ,s

" Y noted that the beam east from the headlight, the sides of the road and a so tosoniodify v H a is of a general conical form and as the forward portions of the intercept as usually the case hasnits axis substantially give an increase of illumination beyond the U parallel with the l-ine"of the roadway at R. barrier Band v ell up to a distance of'say 6 At a distance of. say50 feet from the car 150 feet from tle headlight at which *pomt'n indicated in 'the diagram by a barrier B, sullicient light is desired to show clearly-andy j the eye-of an observer placed at 42 inches car orpedestriar or obstructionin he roa from the ground would be a" proximately Coming now :o the means by which we in the axis of the light cone. his distance eflect the result reference is made to than". of 42 inches is mentioned as that usually embodiment shown in Figs. 7 and 8. Asap g set by-highway commissions as about the pears in Fi 7, our invention may haveone Y fair minimum of the. eye level of the pedesform of em din lent as a plate onscreen of trian, 'The distance of 50 feet between the glassadapted to be substituted for the usual? headlight H and the barrier Bismentioned glass headlight front. This plate of the as illustrative of-about that arbitrary disform shown consists'of adisk crossed units-" tance beyond which the presence of any rear face by transverse prismatic ribs'o'f glaring re s at the eye level is most danvariant angulari 1y, and in the embodiment;

gerous an most annoying, it'being under- I shown having o1 its frontface lateraliver stood that. as approaching cars near each fical elements-f0 rmed by a cylindricalcon' Y" other in passing, the eyes of the adriver'lxend cavity on the fro; it of the-lens indicated at 8 9g y to ass beyond the cone of. illumination. in Figs. 8 and 9. This may becoucav'ed as n Fig. 2 which is a plan, view, the interin Fig. 8 or eccel tric as in Fig. 9. I cept of the light conewiththe roadway is It is to beundersto'od throu houtthis de-"ijfj indicated by the parabola I of which the scription that we do not con e ourselvesj brightest part is the prtion I. to prisms, and th at where prisms are shown 95 I; In Figs. and 4 the light cone 0 is illu'so'r ascribed, lent cular elements'may be sub trated as'depressed so that its'upper margin stituted, or vice 1 'eisa. Neither do we limit C is below the level of the top ofthe ourselves to the exaet'dispositionof anyof barrier 13. This brin the intercept I these elements; S1OW11 or described 35 nearerto the headlight so that. the nearer specifically claimed as such, it being under '1 portion of the intercept has a ortion I stood that the 'far rangementfor grou ingfof of much greater brightness. T e bright the separate elem ants and their relative ness of the'illumination at I is of course position may be varied considerably"withiiu inversely as the square of the distance along departing from $16 spirit ofour itiventiom] 4. the axis, but proportionately it appears even Re errin again to the embodirn'ant.ill-us: ,1 brighter on account of its intensity relative tratedin Figs. 7 and 8, it'will be noted-that to the more nearly dark or unilluminated in the form show] 1, the v ntral prismatidrih roadway immediately in-front'of; the car? and the,tw0 next ladjae iit aretor thepur Conversely the portion in front of an car poses of illustratdn sholwnasofthe-saine, appears much darker in relation to this can angularity and are designated as a, 'oup cessively bright area I. A ain the portions at 1. Above this group 1n theform s own, of the IIItBl'CGEt I ahead 0 the area I are is a group of prisms indicated at .2 .of suerelatively dar er or-less illuminated. This cessive decreasm angularity from the c'enrelative unevenness of distribution of illuter upward. Be aw the central roup aliisw mination is a serious factor and is perhaps another group 2 of successive ecreasevin one reason why headlights have been set angularity from ihe center downward. In with theaxis of the light cone parallel with this form, while tl .e arrangement and grada the road with the resultant glare which has tion of the prisms are symmetrical there is become such a menace to night travel as included the three classesof prismshereto-fl to invoke rules and laws a-gainst it. It is fore refer-radio. [hat is to say prisms hays the object of a our invention to overcome iuga sole or part a1 function ofdepressingl f these difiiculties by means which will be dethe light rays bel w eye level prisms augscribed and. disclosed hereinafter; merited to increasrthis depression .of rays, These moansinvolve initial depression of as Well as the. lat 1'81 elements, in this 'cas the light ofthe vehicle lamp, and a redis lenticular rather t ian prismatic, which con tribution of one or more parts of the light stitutes the lateral deflecting element forsid in such manner as to overcome the difliculillmnination. Y i L ties above enumerated. In Fig.6 we have As heretofore suggested, the functiomof shown a diagrammatic sideview of a. light the lateral di 'ergi: 1g elements may bemodicone 0Q depressed asin Figs. 3 and 4 but @fied as illustrated n Fig. 9 where the lenses.

45 teman are employed in adjacent headlights as at H--H. The lateral elements of the inner' edge of each may be of less divergent efiect than the outcrsides so thatthe intersection of the adjacent light cones will be free from over-brilliancy.

The functions of the variant angles of the prisms may be best understood}; reference to the embodiment shown in ig. 10. In that fi re, the prismatic elements have been num red, beginning at the top, 11 to 16, inclusive. These six prisms are proressivel-y au ted to deflect light near t 9 vehicle. he succeeding four prisms, 17 to 20, inclusive, are normal depressor prisms merely intendedto draw the beams downward to the required level. The prisms 21 to 25, inclusive, constitute a group of prisms decreased from the normal depressor prisms, the decrements being such as to tend to lift the transmitted rays toward the horizontal. In this group are shown prisms with slightl increasing decrements,- as at 21 to 28, tend ing to permit more nearly horizontal rays. Prisms of reversed angle 25 and 26, tend still further to lift the rays toward or beyond horizontal. 1

It is to be noted that the face 24 is a plain surface owing to the fact that at this point the angle of decrement is the same as the angle of the normal depressor risms. In actual practice, all or any of t ese forms of prisms of decreased angle may housed in any order.

this fi re also is shown a modification of the atcral deflecting elements. At 27, we'have indicated 0 positely faced prism elements mounted on t 1e upper face of the screen for the purposes of securing lateral 40 deflection of the upper part of the beams for side illumination.

We thus obtain a more useful distribution of light on the road ay than can be given by the simple reflecting sysloss in the total light flux delivered by the reflector. In all ordinary constructions of headlight a portion of the light passes directly'out of the front of the reflector while 59 the remainder is reflected and directed thereby into an a proximately. parallel or sligilglgtlverging am. Our construction is toward the fullest utilizationof this beam, but it also tends to deflect in a generallydownward way those rays which strike the refracting screen directly from the lamp without being reflected. These beams are too much scattered ordinarily to produce"any unpleasant' glare, but, it is desi'zablethat they be utilized as far as may be toimtgrovathe illumination on the roadway, and

our 'refractingystem herein defl lch'aa to tendtoward this re- 2. light having d even obtain this with an insign ficant a generally downward deflection proelements, their angles, dis osition and com hination of classes may 0 viously be used, all without depart' from the-spirit of our invention, 1f wi in the limits-oi the ap ded claims. I

at we therefore claim and desire to secure by Letters Patent is: p g

1. A refractive screen for an automobile headlight having transverse prisms on its rear face for the downward refraction of light rays, the forward face of said risms having a cylindrical concavity for e lateral refraction of the rays paseingthrough the ends of thetransveme prisms.

A 've screen for a vehicle headtranaverae prisms on its face de reused for the downward refrae' tion of t rays, theforward face of said pngns having an eccentric cylindrical c'oncavity for the lateralrefractzonof the rays face disposed for the downward refraction of light rays, the forward face. of said prisms havin a cylindrical con'cavityfor the lateral roll-action of the rays passing through the ends of th e transverseprisms. 4. refractive device for use with a headlight having a reflector, c' of a member having transverse prismatic sur faces-of downward refractive'action on the reflected rays and havin a surface so formed as to refract the re ected emerging re s on one side of an axial vertical plane i1 the reflector laterally awayfrom said p ane. f 5. A refracting screen for a vehicle headlight com sing a transparent plate, having; para] el transverse across its rear face, the portion of said plate passing through the ends of transverse prism' s extending" prisms on the lower,

' at apoint.

adjacent the center thereo downward havmg decreasing rafrac front face adapted to disperse t e beam late I i 6. n a vehicle [headlight in combination, a substantially arabohc, reflector and a refracting screen avin'gfa ,lnrality of horilee, and-a resultant been with respect to a wertical in testimony whereof we aflix our plerneAthrouffil the center offsaid screen. tures 'in presence of twc witnesses.

re ctive screen or use with a headlight having arefiector comprising i g g g 5 surfaces of variant vertical distributive dis- V persion and suriaees of variant lateraldis- Witnesses: w tributive dispersion at and beyond the in Enwm N. Gonm u, tereept of the roadway. [Lorna BELL. 

